Crimping ferrule with insert rings of hard material



Oct. 21, 1969 w. TEAGNO 3,474,399

CRIMPING FERRULE WITH INSERT RINGS OF HARD MATERIAL Filed March 5, 1967 United States Patent 3,474,399 CRIMPING FERRULE WITH INSERT RINGS OF HARD MATERIAL Wladimiro Teagno, Regina Margherita, Turin, Italy, assignor to AMP Incorporated, Harrisburg, Pa. Filed Mar. 3, 1967, Ser. No. 620,381 Claims priority, application Italy, Mar. 9, 1966,

,368/ 66 Int. Cl. H01r 5/10; H02g /08; F16g 11/02 US. Cl. 339-276 5 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a crimpable ferrule for an electric terminal or connector.

It has been known to provide crimping ferrules with outer annular rims to obtain a relatively smooth outer surface after crimping these projections inwards for engagement with an electrical conductor.

An object of the invention is to provide an electrical terminal or connector having a crimpable ferrule provided with one or spaced projections extending outwardly from an exterior surface of the ferrule and force-driving means in alignment with the projection or projections which is or are driveable into electrical and mechanical engagement with the electrical conductor means thereunder when the projection or projections is or are inward- 1y deformed.

Another object of the invention is the provision of ferrule means of an electrical connector having an irregular exterior surface prior to being crimped and a substantially smooth surface after being crimped.

A further object of the invention is to provide an electrical connector having spaced force-applying means to apply crimping forces to electrical conductor means at spaced locations when the force-applying means is subjected to crimping pressure.

An additional object of the invention is the provision of force-applying means at spaced locations of a ferrule member to force areas of electrical conductor means adjacent the areas to be crimped by the force-applying means into tight engagement with the ferrule member.

A still further object of the invention is to provide ferrule means having force-applying means with the forceapplying means being of harder material than the ferrule means.

Still an additional object of the invention is the provision of an electrical terminal or connector that is crimpable onto electrical conductor means with relatively small crimping pressures.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the in- 3,474,399 Patented Oct. 21, 1969 vention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

An embodiment of the invention is now described with reference to the accompanying drawings in which:

FIGURE 1 shows a partially-sectioned perspective view of a crimpable ferrule according to the invention;

FIGURE 2 shows a longitudinal section of the ferrule of FIGURE 1 located about a wire to which it is to be crimped; and

FIG. 3 shows a section corresponding to that of FIG- URE 2 of the ferrule crimped to the wire.

The crimpable ferrule comprises a metal sleeve 1 formed with circumferential corrugations or projections 2 each having an outwardly-directed peak 3 and an inwardly-directed trough 4 containing a metal annular member 5. The corrugations 2 and the annular members 5 are of generally rectangular cross section and are dimensioned so that each annular member 5 sits in its trough 4 with the inner surface of the annular member 5 substantially flush with the inner surface of the sleeve 1 as can best be seen in FIGURE 2. Each annular member 5 is split to leave a gap 6 between the adjacent ends 7.

In FIGURE 2 the sleeve 1 is shown fitted about a wire '8 to which it is crimped by means of a crimping tool (not shown) having dies with operative faces with cooperate to form a crimp of O-shape. The tool dies are located about a corrugation 2 and then operated to force the corrugation 2 inwards until its outer surface is substantially flush with the adjacent parts of the sleeve 1. This action causes the annular member 5 to reduce in diameter and be pressed into the wire 8 to give a connection of high mechanical strength and good electrical conductivity between the wire 8 and the sleeve 1. The tool is applied in the same manner to the remaining corrugations 2 to complete the connection of the ferrule to the wire 8. Of course, in accordance with conventional crimping techniques, all corrugations may be crimped simultaneously. The completed connection shown in FIGURE 3 has a substantially smooth outer surface.

The ferrule may have one or any reasonable number of corrugations and annular members according to the purpose for which it is to be used. The ferrule may form part of an electric terminal or connection, that is, it may be seucred, probably integrally, to an electric contact element or it may constitute a connector for splicing two wires.

It has been found advantageous to make the sleeve 1 of a malleable material and the annular members 5 of a harder material.

A ferrule according to the invention is particularly useful for making electrical connections to aluminum cables. For this purpose the sleeve is made of a malleable aluminum alloy and the annular members of steel or hard aluminum alloy. It has been found that the sharp edges of the annular members bite into the cable under relatively small crimping pressures and provide good resistance to pulling the cable from the ferrule. The corrugations may have the same dimensions as the annular members.

It will, therefore, be appreciated that the aforementioned and other desirable objects have been achieved; however, it should be emphasized that the particular embodiment of the invention, which is shown and described herein, is intended as merely illustrative and not as restrictive of the invention.

The invention is claimed in accordance with the following:

1. A crimpable ferrule for an electric terminal or connector comprising a sleeve of electrically conductive malleable material formed with a circumferential corrugation having an outwardly directed peak and'an inwardly directed trough, and an annular member of electrically conductive material harder than the material of said sleeve and located within the trough, with its inner surface substantially flush with an inner surface of said sleeve.

2. A ferrule according to claim 1, in which the corru gation and the annular member are each of generally rectangular cross section.

3. A ferrule according to claim 2, in which the annular member is split to leave a gap between the adjacent ends.

4. A ferrule according to claim- 1 in which the sleeve is formed with a plurality of corrugations each having an annular member located within its troughi 5. A electrical connector comprising a ferrule member of electrically conductive malleable material for crimping ontoelectrical conductor means, said ferrule member having projection means extending outwardly beyond an exterior surface of said ferrule member, said projection means having trough means disposed therein along an interior surface of said ferrule member; and

force-applying means of electrically conductive material 4 harder than the material of said ferrule member in said "trough means and having'an'inner surface substantially flush with said interior surface of said ferrule member.

References Cited UNITED STATES PATENTS 650,860 6/1900 McTighe 287 78 X 1,886,086 11/1932 Damon 287109 X 2,008,227 7/1935 Reilly 339-276 X 10 2,490,809 12/1949 Holke 287109 2,965,699 12/1960 Bollmeier 339276 X 3,149,861 9/1964 Larsson 285382.2 X 3,243,758 3/1966 Frant et a1. 339-276 X 1 FOREIGN PATENTS 229,040 12/1943 Switzerland.

MARVIN A. CHAMPION, Primary Examiner 

